diff --git a/CMakeLists.txt b/CMakeLists.txt
index e39c421..4965a9c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,9 +2,15 @@
 cmake_minimum_required(VERSION 3.1)
 project(moonlight-common-c LANGUAGES C)
 
+option(USE_MBEDTLS "Use MbedTLS instead of OpenSSL" OFF)
+
 SET(CMAKE_C_STANDARD 11)
 
-find_package(OpenSSL 1.0.2 REQUIRED)
+if(USE_MBEDTLS)
+  add_definitions(-DUSE_MBEDTLS)
+else()
+  find_package(OpenSSL 1.0.2 REQUIRED)
+endif()
 
 aux_source_directory(src SRC_LIST)
 aux_source_directory(enet SRC_LIST)
diff --git a/appveyor.yml b/appveyor.yml
index 18f5ea6..b53de00 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -15,9 +15,20 @@ environment:
     - APPVEYOR_BUILD_WORKER_IMAGE: Ubuntu
       CC: gcc
       CXX: g++
+    - APPVEYOR_BUILD_WORKER_IMAGE: Ubuntu
+      CC: clang
+      CXX: clang++
+      CMAKE_ARGS: -DUSE_MBEDTLS=ON
+      PREBUILD_CMD: sudo apt install libmbedtls-dev
+    - APPVEYOR_BUILD_WORKER_IMAGE: Ubuntu
+      CC: gcc
+      CXX: g++
+      CMAKE_ARGS: -DUSE_MBEDTLS=ON
+      PREBUILD_CMD: sudo apt install libmbedtls-dev
 
 before_build:
   - 'git submodule update --init --recursive'
+  - 'eval "$PREBUILD_CMD"'
 
 build_script:
   - 'mkdir build_debug'